Shift rockers are known shift elements for carrying out gearshifts in a manual transmission. The shift rocker is curved or fork-shaped and is mounted to pivot relative to the transmission housing. It engages with sliding blocks in an annular groove of a shifting or sliding sleeve, which shifts the desired gear. The shift rocker is actuated by a shift rail or shift rod arranged to move longitudinally in the transmission housing and connected to the shift rocker by a coupling joint. This causes the shift rocker to pivot in one direction or the other.
From DE 43 42 957 A1 by the present applicant a shifting mechanism with a shift rocker of this type has become known. The pivoting mounting of the shift rocker is effected by means of two pins fixed on the housing, which engage in corresponding blind-hole bores in the shift rocker and thus on the one hand enable a pivoting movement about a pivot axis defined by the pins, and on the other hand allow some axial play so that the sliding blocks can slide within the annular groove of the sliding sleeve without catching. In this known shifting mechanism the shift rocker's pivot axis defined by the pins is arranged horizontally.
Problems can arise if the pivot axis is arranged not horizontally but vertically—because in relation to the engagement of the sliding blocks in the annular groove of the sliding sleeve various situations can exist. The shift rocker then rests with its full weight, via the upper sliding block, on the bottom of the annular grove in the sliding sleeve, whereas there is some play between the lower sliding block and the annular groove. This has the disadvantage that the upper sliding block is continually subjected to wear and the lower sliding block slips out of the annular groove (downward), so that the overlap is no longer optimal. In the prior art the engagement of the shift rocker in the shift rod is so designed that a corresponding projection or finger of the shift rocker engages, from below, in a groove of the shift rod, so that no gravitational force is transmitted from the shift rocker to the shift rod. Accordingly, as the upper sliding block becomes progressively more worn the play in the vertical direction between the shift rocker and the shift rod also increases, which reduces the overlap and results in increased loading of the shift rod and the shift rocker.